A media service may be provided to one or more user devices by a media server or a group (e.g., cloud) of media servers. A media server may be or include a machine configured to provide one or more user devices with a datastream that communicates (e.g., streams) a set of one or more media files. For example, such media files may represent prerecorded music (e.g., songs), in which case such a datastream may be described as a network radio service (e.g., Internet radio service). As another example, such media files may represent prerecorded video (e.g., shows or clips) and may be described as a network video service (e.g., Internet television service). In various situations, such media files may include one or more advertisements (e.g., stored as audio files or video files).